of four treatments that used four glass jars (capacity, 110 mL) each and a final treatment with 12 seeds per treatment. The treatments were as follows: treatment 1, 10% SSW and 1:10 MS 10% SSW; treatment 2 (SI), seeds imbibed in distilled water for 16
Claudia A. Espinosa-Leal and Silverio Garcia-Lara
Sharon Sowa and Eric E. Roos
Infrared spectroscopy was used to measure biochemical changes during bean (Phaseolus vulgaris L.) seed imbibition. Transmission spectroscopy of excised embryonic axes revealed changes in lipid phase (gel to liquid crystalline) and protein secondary structure within the first 15 min of hydration. Spectral changes in seed coats, cotyledons, and axes during the first 2 hr of imbibition (measured in vivo) were detected using photoacoustic sensing. Onset of seed respiration could be detected as early as 15 min after addition of water. CO2 production, demonstrated by the appearance of a double peak centered at 2350 cm-1, increased with time of imbibition. Infrared photoacoustic spectroscopy of intact seeds holds promise as a method for non-invasive viability assessment.
Shahid N. Chohan and Terence A. Brown
The RNA content of tomato seeds was shown to increase when the seeds were imbibed in water. This increase was due mainly to an increase in nuclear RNA, the polysomal content declining and the ribonucleoprotein fraction remaining constant. The poly(A)+RNA population also showed a gradual increase, again due to a high de novo synthesis rate in the nucleus. In the presence of 200 μM abscisic acid (ABA), the total nuclear DNA failed to increase in the manner seen with water imbibition, leading to an overall decline in RNA during the first 1.5 h. The polysomal and ribonucleoprotein fractions were unaffected by ABA. The decline in total nuclear RNA was due primarily to a major decrease in the nuclear poly(A)+ content of seeds imbibing with ABA. This reduction in de novo transcription may be a factor responsible for the inhibitory effect that ABA has on germination of tomato seeds.
Guodong Liu, D. Marshall Porterfield, Yuncong Li, and Waldemar Klassen
fitted with time (t, day) in the following formula: where a is the maximum CWU value per corn seed and b is the constant of water uptake rate by the seed with or without H 2 O 2 , and t 0 is the initiation time of seed imbibition in this study. Thus
Luther Waters Jr., Rhoda L. Burrows, Mark A. Bennett, and John Schoenecker
A series of experiments exploring the effect of seed moisture and transplant management techniques was conducted with sh2 and su sweet corn (Zea mays L.). The use of seed and transplants in a progression of developmental stages from dry seed to moistened seed to 14-day-old transplants showed that moistened seed had no impact on plant `growth and development. Use of transplants generally had little impact beyond decreasing percent survival and plant height. Increasing the age of transplants reduced the time to maturity and harvest. Increasing the size of the transplant container (paper pot) decreased the time to harvest for younger seedings, but had no other effects. Premoistened seed were successfully held at 10C for up to 72 hours without damage following moisturization. Delays in irrigation of up to 2 days after planting moistened seed had no detrimental effects on sweet corn emergence and growth.
Yuliya A. Salanenka and Alan G. Taylor
, and pepper seeds were only permeable to nonionic fluorescent tracers (coumarin 1 and 151), and embryo tissue revealed strong fluorescence after seed imbibition and before radicle emergence. No other tracers were detected in the endosperm or embryo
Warley M. Nascimento, Jairo V. Vieira, Giovani O. Silva, Kathleen R. Reitsma, and Daniel J. Cantliffe
., 2007 ), and high temperatures during carrot seed imbibition may affect sensitivity to low oxygen tensions ( Corbineau et al., 1994 ). High seed vigor is necessary for tolerance to environmental stress ( Heydeker, 1972 ), including high temperatures
Germination of `Fond May' eggplant seeds at 25°C could be increased by after-ripening fruit or fresh seed treated with KNO3 or GA3 or priming. There were high amount of starch and low amount of soluble sugar in after-ripening seed or primed seed. The amount of soluble sugar in after-ripening seed was higher than that in control seed before the radicle protrusion at 25 °C and 25/30 °C. Starch amount in after-ripening seed imbibed at 25/30 °Cwas significantly high. Soluble sugar in un-after-ripening seed imbibed at 25 °C for 2-3 days had higher amount and the high activity of β-amylase was appeared in the second days. Activity of amylase in primed seed imbibed at 25 and 25/30 °C for 3 days increased. The activity of endo-β-mannanase was high in after-ripening or priming or GA3 treated seed at 25 °C.
Kwang-Hyun Baek and C.B. Rajashekar
Effects of hypoxia on germinating bean seeds (Phaseolus vulgaris cv. Tendergreen) were examined by imbibing them in water for various lengths of time. Hypocotyl elongation under hypoxic conditions and recovery from hypoxia in bean seeds were determined. Oxygen concentration in the water began to decrease sharply after 12 h of seed imbibition and had declined by more than 63% after 3 days of seed imbibition. When seeds were germinated on 0.8% agar after 24 h of imbibition, the hypocotyl elongation was reduced by about 70% compared to the seeds with no hypoxia, and longer imbibition resulted in poor or no germination. Exogenous hydrogen peroxide (20 mm) in water increased the oxygen concentration from 250 to 350 mm in the presence of seeds and was considerably higher after 3 days of seed imbibition than that in the control. Hypocotyl elongation occurred in seeds submerged in water containing hydrogen peroxide up to 72 h while none was observed in water. This was comparable to hypocotyl elongation under non-hypoxic conditions. Hypoxia in imbibing seeds was overcome by the high oxygen levels in the medium resulting from reaction of hydrogen peroxide with seed catalase and catalytic metal ions. Considerable catalase activity was detected in germinating seeds and the use of a catalase inhibitor, aminotriazole, suggests that the enzyme plays an important role in the release of oxygen into the medium. Of the catalytic metals, the seed content of iron was dominant and was about 6 folds higher than that of either copper or manganese.
Dennis Ray, Steven Smith, and Mark Hurlburt
Lettuce (Lactuca Sativa L.) seeds imbibe water but most fail to germinate, This phenomenon now termed “thermodormancy” is prevalent in arid and semiarid climates like the southwest desert regions, Inheritance studies of thermodormancy were performed in two lettuce cultivars, Dabora (Dutch butterhead) and PI 251245 (a plant introduction from Egypt). Dabora will germinate up to 27 C and PI 251245 up to 36C. Reciprocal crosses were made. Pericarp color was used as a marker to determine successful crosses. Dabora X PI 251245 was used to estimate the heritability of thermodormancy by germinating seed from 10 F3 families and 160 F4 families at “high” temperatures.